STM 3305 Metal Part 3

What is the minimum durability of a canned food?

• The period of time under normal storage conditions during which a product will remain fully marketable and will retain any specific qualities

• The period of time under normal storage conditions after which the product will not be fit to eat

• The period of time under normal storage conditions during which a product will remain fully marketable but may lose some specific qualities

• The period of time under normal storage conditions after which the product will not be safe to consume

What are the three main factors that affect the shelf life of canned foods?

• Sensory quality, nutritional stability, and interactions with the container

• Color, flavor, and texture

• Corrosion, iron dissolution, and lead contamination

• Tin toxicity, aluminum dissolution, and lacquer effectiveness

What is the role of tin in canned foods?

• It protects the steel base-plate and provides a chemically reducing environment

• It prevents color loss and flavor loss

• It minimizes product oxidation

• All of the above

What factors affect the dissolution rate of tin from the can surface?

• Time and temperature, exposure of the tinplate, tin-coating weight, type and composition of the product, and presence of certain ions

• Acidity of the product and presence of nitrates

• Heat, oxygen, nitrate, chemical preservatives, and dyes

• All of the above

What is the legal limit of tin in food products?

• 100 mg kg-1

• 150 mg kg-1

• 200 mg kg-1

• 250 mg kg-1

What can cause internal corrosion in canned foods?

• Insufficient or ineffective lacquer

• Formation of embossed codes on can ends

• Stress corrosion cracking

• All of the above

What is the main cause of sulfur staining in canned foods?

• Residual oxygen in the headspace

• Presence of iron from steel exposure

• Sulfur compounds from protein in the product

• All of the above

What can cause external corrosion in canned foods?

• Condensation due to temperature fluctuations

• Label with high chloride or sulfate

• Incomplete drying

• All of the above

What is the risk associated with high levels of iron in canned foods?

• Unpalatable flavor and color changes

• Toxicity and health hazards

• Corrosion of the can

• None of the above

What is the main purpose of using lacquers in canned foods?

• To limit the dissolution of tin into the product

• To prevent external corrosion

• To enhance the flavor and color of the food

• To provide a chemically reducing environment